Scientists Have Figured Out How to Hit the ‘Pause Button’ on Human Life

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Scientists Hit the “Pause Button” on Human LifeAdela Stefan / 500px - Getty Images
  • Researchers recently examined stem cells to see if they could hit the “pause button” on human development.

  • By inhibiting a series of chemical reactions known as the mTOR signaling pathway, the team found thta they could induce a state very similar to diapause, in which an embryo will temporarily hold off on implanting into the uterus until conditions are favorable.

  • The findings could have serious implications for reproductive health treatments like in vitro fertilization (IVF).


As venerated mathematician Dr. Ian Malcolm once said, “life finds a way.” That’s shockingly true. Some version of life on Earth has lasted through heat waves, ice ages, meteorite impacts, mass extinctions… the list goes on. And so does life.

But the biological tenacity and ingenuity necessary for survival is not exclusive to the grand story of all life on our planet. Individual species, or even individual organisms, have remarkable adaptations that allow those creatures to continue their genetic lineage through significant hardship.

One of those adaptations is a phenomenon called diapause. It’s basically the ability to delay a pregnancy until conditions are the best they can be to carry and birth an offspring. A fertilized embryo will temporarily hold off on implanting in the wall of an animal’s uterus until conditions are right, pausing the biological development of that embryo as a result.



For example, if a bear gets pregnant when it is particularly thin or malnourished (potentially because it’s the wrong time of year), that animal can enter diapause and basically hold the pregnancy in stasis for a while. When it has had time to fatten up and conditions are more favorable, the pregnancy will move forward as if nothing had happened.

A lot of mammals are able to do this—hit the “pause button” on creating new life until the time is right. And according to a new paper published in the journal Cell, humans may be able to do it, too.

Or, at least, it could be done to us. Using, according to a press release, “human stem cells and stem cell-based blastocyst models called blastoids,” the team behind the paper took a look at whether or not this “pause button” activated in humans. And they found something interesting—if the researchers inhibited a series of chemical reactions known as the mTOR signaling pathway, the stem cells and blastoids would enter a state that was extremely similar to diapause. It would even only work within a certain phase of development, just like diapause.

On top of it all, the whole thing is reversible. The stem cells and blastoids went into “diapause” whenever they were given an mTOR, but once that pathway is un-inhibited, everything goes back to normal and development proceeds as if nothing had ever happened.



So, yes—according to this test, in theory, human pregnancies could enter a diapause-like state if properly induced. “This potential may be a vestige of the evolutionary process that we no longer make use of,” Nicolas Rivron, one of the authors of the study, said in the press release. “Although we have lost the ability to naturally enter dormancy, these experiments suggest that we have nevertheless retained this inner ability and could eventually unleash it.”

And unleashing it could have some serious benefits if we learn how to do it properly, especially in the realm of reproductive health treatments like in vitro fertilization (IVF). “On the one hand,” Rivron said in the press release, “undergoing faster development is known to increase the success rate of in vitro fertilization, and enhancing mTOR activity could achieve this. On the other hand, triggering a dormant state during an IVF procedure could provide a larger time window to assess embryo health and to synchronize it with the mother for better implantation inside the uterus.”

The researchers remain optimistic and excited for the ways in which this work could be built upon in the future. But for now, we’ve learned one more thing about our bodies—they can do some wild things, even if we don’t know about them.

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